Portion of a footwear sole



FIG. 1 is a perspective view of a portion of a footwear sole, showing my new design;

FIG. 2 is a bottom plan view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a right side view thereof; and,

FIG. 5 is a rear view thereof.

The broken lines showing a shoe sole throughout the views represent the environmental context in which the design resides, but they form no part of the claim. 

The ornamental design for a portion of a footwear sole, as shown and described. 